Pichia Stipitis
Mostrando 13-24 de 34 artigos, teses e dissertações.
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13. Characterization of Xylose Uptake in the Yeasts Pichia heedii and Pichia stipitis
The kinetics of xylose uptake were investigated in the efficient xylose fermenter Pichia stipitis and in the more readily genetically manipulated, strictly respiratory yeast Pichia heedii. Both yeasts demonstrated more than one xylose uptake system, differing in substrate affinity. The Km of high-affinity xylose uptake in both organisms was similar to that o
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14. Ethanol Reassimilation and Ethanol Tolerance in Pichia stipitis CBS 6054 as Studied by 13C Nuclear Magnetic Resonance Spectroscopy
Ethanol reassimilation in Pichia stipitis CBS 6054 was studied by using continuous cultures, and the oxidation of [1-13C]ethanol was monitored by in vivo and in vitro 13C nuclear magnetic resonance spectroscopy. Acetate was formed when ethanol was reassimilated. The ATP/ADP ratio and the carbon dioxide production decreased, whereas the malate dehydrogenase a
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15. Cloning and Characterization of Two Pyruvate Decarboxylase Genes from Pichia stipitis CBS 6054
In Pichia stipitis, fermentative and pyruvate decarboxylase (PDC) activities increase with diminished oxygen rather than in response to fermentable sugars. To better characterize PDC expression and regulation, two genes for PDC (PsPDC1 and PsPDC2) were cloned and sequenced from P. stipitis CBS 6054. Aside from Saccharomyces cerevisiae, from which three PDC g
American Society for Microbiology.
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16. Molecular Cloning of XYL3 (d-Xylulokinase) from Pichia stipitis and Characterization of Its Physiological Function
XYL3, which encodes a d-xylulokinase (EC 2.7.1.17), was isolated from Pichia stipitis CBS 6054 genomic DNA by using primers designed against conserved motifs. Disruption of XYL3 eliminated d-xylulokinase activity, but d-ribulokinase activity was still present. Southern analysis of P. stipitis genomic DNA with XYL3 as a probe confirmed the disruption and did
American Society for Microbiology.
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17. Utilization of Xylan by Yeasts and Its Conversion to Ethanol by Pichia stipitis Strains †
Yeasts able to grow on d-xylose were screened for the ability to hydrolyze xylan. Xylanase activity was found to be rare; a total of only 19 of more than 250 strains yielded a positive test result. The activity was localized largely in the genus Cryptococcus and in Pichia stipitis and its anamorph Candida shehatae. The ability to hydrolyze xylan was generall
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18. High-efficiency transformation of Pichia stipitis based on its URA3 gene and a homologous autonomous replication sequence, ARS2.
This paper describes the first high-efficiency transformation system for the xylose-fermenting yeast Pichia stipitis. The system includes integrating and autonomously replicating plasmids based on the gene for orotidine-5'-phosphate decarboxylase (URA3) and an autonomous replicating sequence (ARS) element (ARS2) isolated from P. stipitis CBS 6054. Ura- auxot
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19. Induction of Xylose Reductase and Xylitol Dehydrogenase Activities in Pachysolen tannophilus and Pichia stipitis on Mixed Sugars
The induction of xylose reductase and xylitol dehydrogenase activities on mixed sugars was investigated in the yeasts Pachysolen tannophilus and Pichia stipitis. Enzyme activities induced on d-xylose served as the controls. In both yeasts, d-glucose, d-mannose, and 2-deoxyglucose inhibited enzyme induction by d-xylose to various degrees. Cellobiose, l-arabin
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20. Phosphorus-31 and carbon-13 nuclear magnetic resonance studies of glucose and xylose metabolism in cell suspensions and agarose-immobilized cultures of Pichia stipitis and Saccharomyces cerevisiae.
The metabolism of glucose and xylose as a function of oxygenation in Pichia stipitis and Saccharomyces cerevisiae cell suspensions was studied by 31P and 13C nuclear magnetic resonance spectroscopy. The rate of both glucose and xylose metabolism was slightly higher and the production of ethanol was slightly lower in aerobic than in anoxic cell suspensions of
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21. Metabolic-Flux Profiling of the Yeasts Saccharomyces cerevisiae and Pichia stipitis
The so far largely uncharacterized central carbon metabolism of the yeast Pichia stipitis was explored in batch and glucose-limited chemostat cultures using metabolic-flux ratio analysis by nuclear magnetic resonance. The concomitantly characterized network of active metabolic pathways was compared to those identified in Saccharomyces cerevisiae, which led t
American Society for Microbiology.
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22. Isolation and characterization of acetic acid-tolerant galactose-fermenting strains of Saccharomyces cerevisiae from a spent sulfite liquor fermentation plant.
From a continuous spent sulfite liquor fermentation plant, two species of yeast were isolated, Saccharomyces cerevisiae and Pichia membranaefaciens. One of the isolates of S. cerevisiae, no. 3, was heavily flocculating and produced a higher ethanol yield from spent sulfite liquor than did commercial baker's yeast. The greatest difference between isolate 3 an
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23. Effect of Oxygenation on Xylose Fermentation by Pichia stipitis
The effect of oxygen limitation on xylose fermentation by Pichia stipitis (CBS 6054) was investigated in continuous culture. The maximum specific ethanol productivity (0.20 g of ethanol g dry weight−1 h−1) and ethanol yield (0.48 g/g) was reached at an oxygen transfer rate below 1 mmol/liter per h. In the studied range of oxygenation, the xylose reductas
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24. Transcriptional Control of ADH Genes in the Xylose-Fermenting Yeast Pichia stipitis
We studied the expression of the genes encoding group I alcohol dehydrogenases (PsADH1 and PsADH2) in the xylose-fermenting yeast Pichia stipitis CBS 6054. The cells expressed PsADH1 approximately 10 times higher under oxygen-limited conditions than under fully aerobic conditions when cultivated on xylose. Transcripts of PsADH2 were not detectable under eith
American Society for Microbiology.